The Senate is slogging through an overnight session as Republican leaders search for ways to secure support for President Donald Trump’s big bill of tax breaks and spending cuts.

Senate Democratic Leader Chuck Schumer of New York said the “hardest choices” for Republicans are still to come. His side plans to bring “amendment after amendment after amendment to the floor, so Republicans can defend their billionaire tax cuts and so they can try to explain their massive cuts to Medicaid to people back home.”

After a weekend of setbacks, the Senate will try to sprint ahead Monday on President Donald Trump’s big bill of tax breaks and spending cuts despite a series of challenges, including the sudden announcement that GOP Senator Thom Tillis won’t run for reelection after opposing the package over its Medicaid health care cuts.